arm64: mm: use ptep_clear() instead of pte_clear() in clear_flush()

In clear_flush(), the original pte may be a present entry, so we should
use ptep_clear() to let page_table_check track the pte clearing operation,
otherwise it may cause false positive in subsequent set_pte_at().

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 42b2547 ("arm64/mm: enable ARCH_SUPPORTS_PAGE_TABLE_CHECK")
Signed-off-by: Qi Zheng <[email protected]>
Acked-by: Will Deacon <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Kefeng Wang <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Pasha Tatashin <[email protected]>
Cc: Qi Zheng <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: Qi Zheng

arch/arm64/mm/hugetlbpage.c

@@ -236,7 +236,7 @@ static void clear_flush(struct mm_struct *mm,
 	unsigned long i, saddr = addr;
 
 	for (i = 0; i < ncontig; i++, addr += pgsize, ptep++)
-		pte_clear(mm, addr, ptep);
+		ptep_clear(mm, addr, ptep);
 
 	flush_tlb_range(&vma, saddr, addr);
 }